The effect of acute spinal cord compression injury on thyroid function in the rat

The effect of acute spinal cord injury on thyroid function was studied in rats subjected to severe spinal cord compression at T1. Serum thyroxine (T4), effective thyroxine index (ETI), and thyroid stimulating hormone (TSH) were measured at 1 and 100 minutes at one, three, and seven days after laminectomy and spinal cord injury. Control animals were subjected to laminectomy only. T4 was decreased at 1 minute after laminectomy with or without spinal cord injury, though the animals with cord injury had a much more profound reduction. The effects on TSH at 1 minute were dramatically different: laminectomy alone caused an elevation of TSH, while spinal cord injury produced a marked decline. At the later time intervals both groups showed gradual normalization of T4 and TSH levels, and at seven days there were no significant differences between the groups. Thus, acute spinal cord compression injury produced a major alteration in thyroid function during the acute phase.